Dynamic and air brake interlock



Dec. 19, 1933 F. s. THOMAS 1,939,866

DYNAMIC AND AIR BRAKE INTERLOGK Filed April 14, 1930 v INVENTORFREDERICK STHOMAS BY%WW ATTORNEY Patented Dec. 19, 1933 DYNAMIC AND AIRBRAKE INTERLOCK 7 Frederick S. Thomas, Tokyo, Ja an, assignor to TheWestinghouse Air Brake Company, Wilmerding, Pa., a corporation ofPennsylvania Application April 14, 1930. Serial No. 443,944

' 7 Claims. (01. 303-3) This invention relates to brakes for railwaytrains, and. more particularly to a brake equipment in which anelectrodynamic brake is employed. a

- With the synchronous motors commonly used on electric locomotives,where the motors are used as generators to effect a regenerative brakingaction, the motors will only operate to generate current when the speedis between certain limits.

For example, if the motors are designed for a synchronous speed ofthirty miles per hour, the

motors when acting as generators will not generate current to anyextent, if thespeed is less than 28 miles per hour or' greater than 32miles per hour, Consequently in down grade service, if the speed exceeds32 miles per hour, the regenerative braking effect will be substantiallylost.

The principal object of my invention is to provide a dynamic brakeequipment and means for 30 cuttinga fluid pressure brake into actionwhenthe speed of the train is excessive in down grade service. r I

In theaccompanying drawing, the single figure is a diagrammatic view,partly in section,.of a dynamic brake controlling apparatus, embodyingmy invention.

The fluid pressure brake apparatus may.com prise a brake valve device 1of the usual constructionhaving an operating handle 2 and adapted tosupply fluid under pressure to the usual brake pipe3 and to vent fluidunder pressure irom the brake pipe so asto effect an application of thebrakes I A valve device for effecting an application of the brakes isprovided comprising a casing 4, having a piston chamber 5 containing apiston 6 and having a' valve chamber 7 connected to a reser-. voir 8 andcontaining a slide .valve 9 adapted to be operated bypiston 6;

,A magnet valve device is provided comprising an electromagnet 10 anddouble beat valves 11 and 12 adapted to be operated upon energizationand deenergization of the magnet 10. The usual brake cylinder 13 isprovided and the usual triple or other brake controlling valve device 39is adapted upon a reduction in brake pipe pressure to supply fluid underpressure to the brake cylinder and upon an increase in brake pipepressure to release fluid from the brake cylinder.

The dynamic brakeapparatus is notv shown in the drawing, since it is notdeemed necessary to a clear understanding of the invention, but it willbe understood that when the dynamic brake is cut in, thecircuit wires 14are connected up so as to be energized by the counter E. M. F. of

the car motor so that the relay 15, connected in said circuit wires,will be energized according to speed of the carand the counter E. M. F.

generated. d

The relay coil 15 controls a switch member 16 and in one position of themember 16, 'a circuit is closed from wire 17 to wire 18, the closing ofwhich circuit is necessary in order that the dynamic brake will beeffective and operative.

In the other position of the switch member 16, a circuit is closed froma wire 19 to the magnet 10, the wire l9 being connected to a-source ofcurrent, so that magnet 10 is energized when the circuit is closed.

interposed in the circuit wire 18 are contacts 7 20 adapted to bebridged by a contact member 21. The contact member 21 is connected by astem 22 to a piston 23, which is contained in a casing 24.

'The chamber 25 at oneside of thepiston 23 is connected by pipe 26 tothe brake cylinder 13., and the piston 23 is subject to the pressure offa coil spring 27 whichurges the pistondownwardly and the switch member21into engagement with the contacts 20. a r

When the dynamic brake is not acting, there 30 is no current flowingthrough the circuit wires 14, so that magnet 10is deenergized. Thevalve12 is then seated by spring 28v and the valve 11 is unseated, so thatfiuidunder pressure is supplied from the usual mainreservoir 29, through'pipe 30 to pipe 31 and passage 32, leading to piston chamber 5 of theapplication valve device 4. Fluid flows through feed groove 33 aroundpiston 6 and charges the valvechamber '1 and reservoir 8 with fluidunder pressure, The spring 34 then maintainspiston 6 in its releaseposition, as shown in the drawing. a T

In operation, when it is desired toapply the brakes, the usualcontroller (not shown) is moved to a dynamic braking position, in whichcircuits are set up for .eiiecting dynamic braking. If the speed of thetrain is not excessive, the relay coil 15 will not beenergized by thecounter E. M. F. of the car motor, sufiiciently to cause movement of theswitch member 16 from the position shown in the drawing. g The circuitwill thus remain closed through th wires 1'7 and 18, so that the dynamicbrake. operates. If the speed of the train is high, the current flowingthrough the wires 14 will be suflicient to energize the coil 15 so as toeffect the movement of the switch member'16 to its upper position. Themovement of the switch member 16 to its upper position effects the openi g of the circuit through wires 17 and 18, so that the dynamic brake isprevented from acting. The circuit is also .closed from wire 19 to themagnet 10, so that said magnet is energized and thereby the valve 11 ismoved to its seat, while valve 12 is unseated. The unseating of valve 12permits the venting of fluid under pressure from the piston chamber.5,,so. that. piston- 6* is shifted outwardly by the fluid-pressureinvalvechamber 7. In the outer position of piston 6,, a, cavity 35 inslide valve 9 connects the brake pipe 3 with a pipe 36 leading to areduction limiting reservoir 37, said reservoir being normally main.-tained at'atmospheric pressure in the release position of the slidevalve 9 throughits connection.

to exhaust port 38.

Fluid under pressure is thenvented from thebrake pipe to effect apredeterminedreduction in: brake pipe pressure by equalization intoreservoir 3'7, and the brakes are applied in. the-usual? to apredetermined degree, the. counter E. M; F.

ofthe car motor will reduce so; that the coil 15 will not be energizedsufiici'ently' to hold the switch member 16in its upper'position and theswitch member willthen move. to" itslowerpossition in which the circuitis'again closed from The';circuit,,h'owever, will still be. open at thecontact 20,1 since; the; switch member 21 is held in open position" bybrakezcylinder' pressure: The magnet lo'is' deen erg'ized'by thedownward'rnovement" of switch member 16; and consequently, the valve12is moved' to its seat; while valve H is unseated. Witlrval've'll'unseated; fluid under pressure issupplied from pipe 30 topistonchamber. 5. andfpist'on 6t is therebyshifted' to release position"The brake'valve. 1. bein'g in' running'po sitinn,the brake pipe 3' willb e:recharged the usualmahner' and' thabrakes will: be released" by therestoration; of" brake pipe. pressure: I When the", brakecylinderpressure has'been reduced to-a predetermined degreeas the-brakes arebeing relasedl, the pistonz23' willf be shifted downwardly by ,spring27,so that the switch member 21; shifted to. its position closingthecircuit throughwireI8; The dynamic: brake; is

then cut into action. By this means, the; dye namic brake is preventedfrom acting until the fiuidlrpressure" brake. has been released,. sothat thebraking. force will'notbe; excessive due to the fiuid'pressurebrake being applied at thesame I time that the dynamic brake iscutt in.

While one illustrative embodiment. of the in vention hasbeendescribed indetail, it is. notmy intention to. limit its scope to that embodiment orotherwise than by the: terms of the:appended claims.

Having, now described my invention, what I claim. as new and. desire tosecure by Letters Patent, is; V

1. The combination with a dynamic brake circuit, oil a car. fluidpressure brake apparatus and means operative'automatically whenithespeed of the car exceeds a predetermined rate. for opening said circuitand. means operated upon opening said circuit for effecting theoperation of said brake apparatus to cause a fluid pressure applicationof the brakes.

2. In a car braking system, the combination with a circuit associatedwith a dynamic brake system, the closure of which permits the dynamicbrake to act, of a fluid pressure brake apparatus, electricallycontrolled means for effecting the operation' of said apparatus to causea fluid pres- .sure. application of the brakes, a switch device forcontrolling said circuit and the circuit of said electrically controlledmeans, and means energized by. a voltage, proportional to the speed ofthe car for operating said switch device.

3:,In azcaa'. braking system, the combination with a; circuit;associated with a dynamic brake system; the closureofwhich permits thedynamic brake td act,.oi ..a.fluid.pressure brake apparatus,electrically controlled'means operative upon energization to effect theoperation of said apparatus to cause a fluid pressure application of thebrakes; a i switch adapted"- in' one position to close said circuit andin another position to close-the circuit or said electrically controlledmeans, and means operated when the speed of the car exceedsapredetermined rate' for" operating" said switch to' open the dynamicbrakecircuit" and closethe circuitof said electrically controlled means:7

4. In a car' braking system, the combination with acircuit associated.with a dynamicbrakesystem, the closure ofwhich'permits the dynamicbraketo act, of a brake pipe, a valve-device'opera atedby'a variation infiuidpressure foreflecting a reductionin" brake pipe'pressure; and a brake:cyiinder-adapted to be supplied with fluid under pressure upon-a:reduction inibrake pipe pressure, a switch for controlling; saidcircuit; and means operated-bybrake cylinder pressureforoperating saidswitch to open' said. circuit: 7

5'. In a car braking system, the. combination with 'a' circuitassociated with a dynamicbrake system, the opening of which preventsthe" dy namic brake from acting, of""abralie cylinder; electrically'controlled means operative upon energizatiorrfor effecting the supply offluid under pressure to the brake cylinder a switch for controllingsaid" circuit and the circuit of saim'electrically controlled means; acontrol circuitthe voltage in which is variedc'according'to the'speedofthe car, and means operated ata predetermined increase in voltage insaid. control circuit for operating said switch to open the dynamicbrake circuit and close the circuit: to said;electrically controlledmeans;

i 6; In a car braking system, the combination with a circuit associatedwith a dynamic brake system, the opening of. which; prevents-the dynamicbrake from acting, of a' brake. cylinder, electrically controlled means.operative upon energization for efiecting the supply of'fluid underpressure to the brake cylinder, a switch for controlling said circuitand the circuit of said electrically controlled means, a control,circuit, the voltage in, whichis varied according to the speed of thecar, means operated upon apredetermined increase in voltage in thecontroltcircuit for operatingsaid switch to open the dynamic brakecircuit and close the circuit to said; electrically controlled means, anadditional. switch for controlling said dynamic. brake circuit, andmeans controlledby brake cylinder pressure for operating said"additional switch.

'7..In a car braking system, the combination system; the opening ofwhich prevents the dynamie brake from acting, of a brake cylinder,

trolled means, an additional switch for controlling said dynamic brakecircuit, and means controlled by brake cylinder pressure and operatedupon a predetermined increase in brake cylinder pressure for actuatingsaid additional switch to open said dynamic brake circuit and upon apredetermined decrease in brake cylinder pressure for operating saidadditional switch to close said circuit. I

FREDERICK S. THOMAS.

